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Monday, 23 September 2013

Not just your health, but also your wallet: Bandsaw Maintenance, and extraction problems.

The other day I got an order from a regular customer to make some bespoke MDF blanks for her craft business' Christmas line. I made up a template out of 12mm MDF, and cut it out on the bandsaw.

Fairly early on I started to notice things didn't sound "quite right", It was cutting fine, and clean etc, but it was whining like it was trying to Rip a 5" slice of English oak.... I stopped and took a look only to find that the guide bearings where totally clogged-up with resin, dust and all kinds of yukkyness from the last three years of fairly hard use.
I should probably point out that, although My Bandsaw, (a record power BS250), is fairly small - 10" bench top model which takes 1/4-1/2" blades, I've been happily using 3/16" and also 1/8" blades in it a lot. I get mine from Trucut, they seem a nice bunch, are helpful, and delivery is always super quick! The only reason not to use smaller blades, that I can see, is the back bearing which only has a finite amount of travel to guide the blade. 3/16" will run with no problems at all. but the very thin 1/8th blades are a little more problematic and can start to hit their teeth on the side bearings - this effects the set of the teeth and starts to cause problems with straight cuts. To get round this I just open up the distance on the side bearings to leave a little extra room.
Anyway before I go too far off on some kind of tangential rant, lets get back to the bearings..... I also have previous of running my bandsaw without the the dust extractor connect. Yes I know. Health and safety: blah, blah, blah, and for all you trolls out there, they're my lungs not yours. You know how it is, quick cut here, trim that bit off etc etc. Anyway all this means that the dust, resin and rubbish just fall away and sit on the bearings, and clogs them up..... GOOD AND PROPER it seems! So much so that the three bottom bearings had totally seized, and would not turn at all, even after a good soak in degreaser, and WD40. It was at this point I concluded that dust extraction was not helping, new bearings were required, and the "not quite right" noise I could hear, was in fact the back of the blade wearing a groove down the centre of the lower centre blade guide! Ooopps!

It is surprisingly easy to work out what size bearings I would need, just measure the knackered ones a quick ruler 6mmx19mmx6mm even more conveniently the current ones were marked 626Z, a standard code for this size and readily available.

Now I've actually had to contact record before to get parts, and If you have too, you might see where I'm heading? So after the first encounter, I picked myself off the floor where i had laid laughing and went straight onto the internet. Plenty of choice in the UK, and far cheaper to buy a pack of ten - may as well change them all, still have 4 new and save the best two old ones for a full set next time.
these ones came from "a popular internet auction site". Ordered Friday, arrived Monday, £4.45 all in! Result! :-)

Really all you need to change the bearings over on this model is a 4mm Allen Key, or hex driver bit. They were a bit stiff to get off, partly because of all the muck that had settled on them, partly, I suspect because I may have torqued the bolts up to " four white knuckles" at some stage.

They're really easy to change, and whilst off a good opportunity to clean it all up properly. And the bottom set are exactly the same, just a little more fiddly due to the table being in the way! I found it easier to assemble the guide bearing assembly for each one first, then slide the whole lot into position rather than add each bit one at a time.

A final clean-up with an old tooth brush, and it's all good! This kind of maintenance is an ongoing one, something that will need doing again at some point in the future. How soon will depend on running hours of the machine, but I have no doubt it would definitely help to prolong this job by simply using the extractor as well!

Not an expensive job, or even one that's unpleasant, well more unpleasant than using the bandsaw, but not as bad as breaking a blade!